In a recent working paper, economists Thomas Buchmueller and Colleen Cary find that one particular kind of restriction does reduce opioid misuse among Medicare beneficiaries:
The misuse of prescription opioids has become a serious epidemic in the US. In response, states have implemented Prescription Drug Monitoring Programs (PDMPs), which record a patient’s opioid prescribing history. While few providers participated in early systems, states have recently begun to require providers to access the PDMP under certain circumstances. We find that “must access” PDMPs significantly reduce measures of misuse in Medicare Part D.
Yet, they also find
no statistically significant effect [of must access PDMP’s] on a key medical outcome: opioid poisoning incidents.
How is this possible?